Former Bosnian Serb leader Radovan Karadzic was convicted by UN judges of genocide for the 1995 Srebrenica massacre, the worst war crime in Europe since World War Two, and sentenced to 40 years in prison.

Serbian President Tomislav Nikolic said Sunday that an attack on the country`s prime minister at a ceremony marking the 20th anniversary of the Srebrenica massacre recalled similar incidents ahead of the 1990s Bosnia war.

An angry crowd hurling stones and plastic bottles forced Serbia`s premier to flee a ceremony Saturday marking the 20th anniversary of the Srebrenica massacre of some 8,000 Muslims in Bosnia, Europe`s worst atrocity since World War II.

Tens of thousands of people, coming by buses, cars, motorcycles and on foot, poured into Srebrenica on Saturday to mark the 20th anniversary of Europe's worst massacre since the Holocaust and to attend the funeral of 136 newly found victims.

Over more than a decade, the International Criminal Tribunal for the former Yugoslavia has indicted 20 suspects for crimes committed in July 1995 at Srebrenica. All were arrested and brought to The Hague.

Pope Francis on Saturday bemoaned the "atmosphere of war" haunting the world as he urged the people of war-scarred Sarajevo to provide an example of how different cultures and religions can co-exist peacefully.